microchip_t1: Add driver for Microchip LAN87XX T1 PHYs

Add driver for Microchip LAN87XX T1 PHYs

This patch support driver for Microchp T1 PHYs.
There will be followup patches to this driver to support T1 PHY
features such as cable diagnostics, signal quality indicator(SQI),
sleep and wakeup (TC10) support.

Signed-off-by: Nisar Sayed <Nisar.Sayed@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>